Nickel anode and method of producing the same, etc



Patented Sept. 8, i925.

aesaaio nan s rains rn rau'r orrics.

1303K VICTWDR HYBIHETTE, Q'F WXLMINGTON, DELAWARE.

NICKEL ANODE AND METHOD PRODUCING- THE SAME, ETC.

Bio Drawing.

To all whom it may concern:

Be it known that 1, Non: Vro'ron HYBI- Name, a citizen of the-United States, residing temporarily at Wilmington, in the a county of New Castle, State of Delaware,

in clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improved nickel as anodes and to a method of producing the same, as well as the improvements in the electrodeposition of nickel therewith.

In my prior application, serial No. 565,758, filed. June 3, 1922, I have described an the production of cast anodes by oxidizing molten nickel and casting the anodes from the oxidized nickel. Such oxidized nickel anodes contain from about 0.1% to 0.25% of oxygen and dissolve so readily, when as used as anodes in the eleotrodeposition of,

nickel, that they cause the bath to become basic.

I have now found that if such an oxidized molten bath is deoxidized, by a suitable de- 3%? oxidizing agent other than carbon, so as to remove the greater part of the oxygen without completely removing it and rendering the nickel malleable when cast, the anodes made from the resulting bath will be of such solubility that they will dissolve at substantially the same rate at which the nickel is plated on the cathode, so that the bath will remain of correct acidity for long periods of time.

If a molten bath of nickel is reduced or deoxidized by carbon, some carbon monoxide that is formed will beabsorbed by the metal, and, when the metal is cast and cooled this gas will give a porous or spongy casting. In order to overcome thissponginess, it has heretofore been attempted to carbonize the metal and subsequently deoxidize it but the desired solubility is thus lost.

I have found, however, that by introduc-- ing into the molten metal a suitable deoxidizer which will form a nongaseous oxide, there'will be noformation and absorption of gas, and the resulting deoxidized metalcan then-be cast into anodes which are not spongy or orous in character, The d oxidizing o the nickel, however, is nots Application filed September 23, 1922. Serial No. 589,995.

complete thatthe metal becomes malleable;

or that it shows more than a small degree of toughness. If the deoxidizer is added in such quantity that the metal becomes malleable or tough, the desired easy solubility is lost. Accordingly, the deoxidized bath is deoxidized without completely removing the oxygen, and I have found that when this is properly done, the resulting metal is ideal for use as anodes for nickel deposition. The anode made of the highly oxi-- dized nickel turns the electrolyte basic, while the fully deoxidized anode turns the electrolyte acid; but where the anode is deoxidized incom letely, according to the present invention, t id anode has the correct solu-.

bility so; that the bath will remain of correct acidity for nickel deposition for long periods of time.

With the ordinary anodes, diiierent electrolytes dissolve the anodes differently, and

the chloride bath dissolves the anodes more readily than the sulphate bath; but the anodes of the 'prese'nt'invention are almost theoretically perfect in their solubility in the baths commonly used for nickel deposition, so that the new anodes can-be used With sulphate electrolytes as well as with chloride electrolytes, etc.

, The method of producing the new anodes is illustrated by the following example:-

Nickel is melted under oxidizing conditions in a reverberatory furnace preferably lined with ordinary clay brick. The slag formed during themelting downof the nickel may be left on the moltennickel, or it may be skimmed ofi'i, or slag ingredients may beadded, but at the end of the melting down and slagging operation-there should be an oxidized metal covered with a fairly neutral silicate slag. The slag should be one which does not attack or destroy the furnace lining, but otherwise it can be; varied in its composition, It should not, how-' ever, contain any large'amount of nickel,

iron, etc., which will react'with the deoxidizer used and reoxidize the bath of molten nickel'afte'r it has been deoxidized to the proper. extent. ,With careful handling of the furnace, a slag covering of-th'e molten bath may not be necessary, but the danger of reoxidizing the metal and absorbing carbon monoxide is such that the bath can be more readil handled when a layer of slag covers it. r the molten nickel has been oxidized and .thereby freed from impunhowever be used in such amount as to af-.

fect the desired solubility of the anodes. With an oxidized nickel such as above described I have used from 01% to 0.2% of metallic aluminum. The right quantity can be readily ascertained. If from time to time small quantities of the aluminum are added and s mples of the molten nickel are taken,

' it is found that the metal changes in color and grain. By producing a set of samples and having them' analyzed and using them for comparison, the proper color and grain slowly.

of the cast metal can be determined. The correct solubility is obtained when the metal contains between about 0.05% oxygen and 0.05% aluminum. The oxygen is for this purpose determined by dissolving in very dilute nitric acid and determining the nickel in the undisso lved residue from which the oxygen is'calculated as NiO.

After the .molten metal has been deox1-' dized to the desired extent, the metal is poured into molds, care being taken not to introduce any carbonaceous" matter. The molds may be metal molds which will rapidly chill the anodes or they may be sand molds in which the metal would cool more The new anodes thus produced can be used general]. .for nickel plating purposes and they ena le a good cathode deposit to be produced without the necessity of adjust ing the acidity of the bath over long periods of time. When the new anodes are usbd, it is unnecessary to add salts to the bath. The anodes can also be used with sul hate electrolytes without the addition of c lorides to the bath.

While I do not wish- ,any theoretical explanation-of the reason for the remarkable results which the new anodes give, yet I believe that the correct solubility depends not only-upon the amount of oxygen carbon silicon etc. that is present but alsb upon the grain of' the metal. If

the grain is fibrousand the metal is tough,

the anodes made therefrom are more or less iIlS0l llb1G-- If ,the oxygen is completely removed by the deoxidizing agent, for example, with magnesium, it' is possible to have an anode that; is malleable and still contains no magnesium; but such an anode does not :readil dissolve; In making the new anodes,

deco ingly, the metal is not completely deoxidized sons to make it malleableand difiito .limit. myself bycultly soluble, but a small and. regulated amount of oxygen is left in the metal such that it has the almost perfect solubility above referred to. Impurities such as copper, iron, etc. are undesirable but may be present in small amount as in ordinary cast anodes, although the nature and amountsof any-impurities present should not be such as interfere with the desired solubility of the anodes. When the anodes are produced in the manner above described, the impurities can be almost completely removed during the oxidizing treatment, so that the anodes cast from the molten metal after the incomplete deoxidizing treatment will be of high purity. .Where the impurities present in the molten bath are not completely re-- moved in this way they-may remain and be present in the cast anodes.

It will thus be seen that the present invention'provgides newv anodes having valuable properties which adapt them for general use in nickel deposition, and with resulting advantages in the nickel deposition such as are unobtainable with any anodes heretofore known, in so far as I am aware. The invention also includes the method of .making the new anodes by an oxidizing treatment of the molten bath and a subse-' quent regulated deoxidizing treatment with a deoxidizer other thancarbon, and casting of the resulting metal. The invention also includes the improved method of electrodeposition in which the new anodes are used and which can be carried out with practically automatic regulation of the acidity and without the necessity for the usual adjustmen'ts of the acidity of the electrolyte.

Theelectrolytic process in which the new anodes are used 1s accordingly one of general application with different electrolytes and for different purposes, but is of special application with sulphate electrolytes and yyithoutthe addition of chlorides, etc. to the at i.

It will be understood that yariations and changes can be made in the particular method of making the anodes, as well as in the baths and in the" electrodeposition in which the anodes are employed.

I claim:

1. The method of producing nickel anodes which comprises oxidizing a nickel bath,..

deoxidizing the oxidized bath with a deoxidizer forming a non-gaseous oxide, and casting the deoxidized metal, the deoxidizing of the metal being insuliicient to render the metal tough and malleable.

2. The method of producing nickel anodes 'stantially free from impurities and contain- 3. A cast nickel anode havinga solubility such that the dissolving of the anode. is substantially the same in the common electrolytes and corresponds with the deposit on the cathode with maintenance of the correct acidit ofthe bath without adjustment.

non-porous castnickel anode subing about 0.05% of oxygen.

5. -A cast nickel anode comprising incompletely deoxidized oxidized nickel. 6. A ni kel anode substantially free from impurities and containing about 0.05% of oxygen. Y

7. A nickel anode substantially free from 16 impurities and non-malleable;

8. A nickel anode consisting of nickel practically free from carbon, silicon and oxygen, and non-'malle'able.

9. A nickel anode substantially free from 20 ing oxygen in effective amounts but less than 2 In testimony whereof I aflix my signature.

NOAK VICTOR HYBINETTE. 

